The present invention relates to a picture reproducing apparatus such as a video cassette recorder (VCR) or a camcorder, and more particularly, to a jitter compensating device for an on-screen display (OSD) in a picture reproducing apparatus. The apparatus according to the present invention is capable of preventing jitter of an OSD screen in the vertical direction, which is caused when an OSD processor mis-recognizes noise as a vertical synchronous signal, the noise component generated according to the state of a tape or a head traveling state when a special-play mode is performed while the OSD screen is displayed in a main screen of a picture reproducing apparatus.
A picture reproducing apparatus having the OSD function may display the OSD screen on a main screen during a special-play mode such as a still picture mode, a forward picture search mode or a reverse picture search mode.
When a general picture reproducing apparatus performs a special-play mode, the video head traces across the video tape differently from when in a normal-play mode. Therefore, an envelope waveform is not flat, and the uneven envelope waveform is manifested on a TV screen as noise.
Thus, when a conventional picture reproducing apparatus performs a special-play mode while displaying an OSD screen in a main screen, a vertical synchronous signal is generated containing errors due to the noise generated by the uneven envelope waveform. As a result, an OSD processor mis-recognizes the noise as a vertical synchronous signal, so that the OSD screen has vertical jitter.
Due to the above problem, the conventional picture reproducing apparatus can not display the OSD screen on the main screen during a special-play mode without jitter.